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The International Atomic Energy Agency says Iran has activated equipment to enrich uranium more efficiently, a move that defies the UN Security Council.
The Vienna-based nuclear watchdog says Iran has started using a second set of 164 linked centrifuges to enrich uranium to up to 20 percent. Experts say at 20 percent, uranium can be turned into weapon grade material much more quickly than less enriched uranium.
But Tehran has denied it has such aims and says its nuclear activities are for peaceful purposes only.